Mashed Potato Casserole is so easy to make with leftover or fresh mashed potatoes!  This mouthwatering side dish is loaded with cheese, bacon and tons of flavor!

mashed potato casserole in a baking dish

Please meet your new favorite, ever, side dish!  You can make this casserole with your favorite leftover Mashed Potatoes, make them fresh and use right away, or use store bought potatoes if you wish!  The plan was to have this recipe out on the blog before Thanksgiving, but, the Roast Turkey and many other side dishes just had to come first.  Besides, this really is a great side dish for any weeknight or whatever occasion. It’s nice to change up things for dinner every once in a while and this side is perfect with a batch of Crispy Baked Chicken Thighs or maybe the always popular London Broil and we love it with our fave Chicken Drumsticks!  I’m keeping this post short and sweet, because it’s just that simple of a recipe.  I’ve linked to our mashed potato recipe within the recipe card below if you want to give ours a try!  Also, if you’re obsessed with potatoes like we are, try out our classic Cheesy Hashbrown Casserole too!

Mashed Potato Casserole Tips and Notes:

Let’s talk about what’s in this potato casserole!  You’ll want a good 4-5 cups of mashed potatoes for this casserole.  I like to make a big batch of mashed potatoes at the beginning of the week.  You can store leftovers in the fridge for a good 3 days, then make this side later in the week.  We doctor up the mashed potatoes with a good amount of Ranch Dressing, sharp cheddar, and parmesan!  The topping is the absolute best, we use more cheese, crushed Ritz crackers, crispy cooked bacon, and green onions!  The topping might be my favorite part, so don’t skip it!

  • You can prep this ahead.  Make as directed, then cool completely if the potatoes are hot.  Leave off the topping until ready to bake.  Cover the dish tightly with foil and refrigerate for up to 2 days.
  • To freeze, prep as directed, without the topping, and do not bake.  Cover the dish tightly with a layer of plastic wrap, and then a layer of foil.  At this point you can freeze for up to two weeks for best results.  I recommend thawing in the refrigerator overnight if possible before baking.  But, they can be baked from frozen if necessary.  Just keep in mind they will need an additional 15-20 minutes to warm through.
  • If you have frozen this casserole and it seems watery during baking.  Give it a good stir and add in a few Tablespoons more milk if necessary.  Then continue baking.
  • If you don’t like ranch dressing, you can leave it out.  Other good subs are a packet of ranch dressing mix, or a bout 1/3 cup of softened cream cheese or even sour cream for some great flavor.
  • If you don’t have Ritz crackers, you can also use saltines, Panko breadcrumbs, or even crushed potato chips!

mashed potato casserole in a spoon



5 from 5 votes

Mashed Potato Casserole

Mashed Potato Casserole is so easy to make with leftover or fresh mashed potatoes!  This mouthwatering side dish is loaded with cheese, bacon and tons of flavor!
Prep 10 minutes
Cook 20 minutes
Servings 8


  • 4-5 Cups Mashed Potatoes
  • 1/2 Cup Ranch Dressing
  • 1 1/2 Cups Cheddar Cheese
  • 1/2 Cups Parmesan Cheese
  • 1 Sleeve Ritz Crackers crushed
  • 3 Tablespoons Butter Melted
  • 8 Slices Bacon Cooked and Crumbled
  • 3 Green Onions Diced


  • Preheat oven to 375 degrees.
  • In a large bowl, mix together the mashed potatoes, ranch dressing, 1 cup of the cheddar, and the 1/2 cup of parmesan cheese.
  • Spoon the potato mixture into a 9x13 inch baking dish.
  • In a medium bowl mix together the crushed crackers and butter.
  • Sprinkle the cracker mixture, and crumbled bacon evenly over the mashed potatoes.
  • Cover the dish with foil and bake for 15 minutes.
  • Remove the foil, place the dish back in the oven and cook for an additional 10 minutes until the topping is golden.
  • Serve immediately topped with green onions if desired.



NOTE:  Once prepared, this casserole can be covered (without topping) and refrigerated for up to 2 days, or frozen for up to 2 weeks.  
NOTE:  If you don't have ranch dressing you can use ranch dressing packet mix, or 1/3 cup of cream cheese or sour cream for more flavor.


Serving: 0.5Cup, Calories: 150kcal

Nutrition information is automatically calculated, so should only be used as an approximation.

Additional Info

Course: Side Dish
Cuisine: American
Like this? Rate & review this recipe below!


Hey! Nice to meet you! I'm Nichole!

Welcome to The Salty Marshmallow! I'm a mom, animal lover, photographer, & kitchen mess-maker. Here you will find the result of my decades-long passion for chasing the best flavors in the kitchen, all meant to be cooked by regular people with busy lives just like you and me.

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  1. 5 stars
    I would eat this as a whole meal! However, after Easter, this will be perfect for a side dish with leftover ham. I am totally saving this for that exact reason.